Canine luteinizing hormone (cLH), which in concert with follicle stimulating hormone (FSH) causes ovulation in a female dog, is a peptide hormone containing an alpha protein subunit of approximately 13,400 daltons and a beta protein subunit of approximately 18,200 daltons. The alpha subunit is shared by a number of other peptide hormones and therefore, specificity is derived from reaction with the beta subunit. D. L. Wolf et al., Nucl. Acids Res., 15:10602 (1987) compared the nucleic acid and amino acid sequences of dog beta LH to that of rat, cow and human, calculating an amino acid sequence homology of 89% with rat, 84% with cow and 74% with human. Calculations based on cDNA sequences archived with GENBANK are similar to those published figures.
Detection of LH levels in the biological fluids of other mammals, particularly humans, has been employed in diagnostic procedures and processes for correlation with ovulation. These processes and products enable one to detect the timing of ovulation for purposes of avoiding or facilitating pregnancy. In humans, LH is an intact molecule which can be detected in blood and, more significantly, in urine. Thus, simple tests for the presence of LH are available for fertility detection.
In canines, however, the study of LH has not revealed its presence in urine. A radioimmunoassay has been described for the detection of cLH proteins in canine serum. However, serum testing of canines to assess the onset of the fertile period is an onerous and impractical method for dog owners and breeders to routinely perform. Thus, processes or products for routine detection of LH in canines has not been pursued as a practical method of detecting fertility.
There exists, therefore, a need in the art of canine breeding, particularly in the breeding of dogs with desirable genetic traits, for an efficient and accurate means for dog owners and breeders to determine the condition of fertility in the dog.